This invention relates in general to instruments and methods of removing a cataractous lens. More particularly, it relates to an instrument and method for cataract disassembly.
Clouding of the natural crystalline lens of the eye is termed "cataract formation". To restore vision, the cataractous lens must be removed. It has been known to perform cataract surgery using a technique which "disassembles" the hard central nucleus of the lens into a number of fragments to be removed progressively from the eye. The nucleus is disassembled using a bent wire hook made out of round stiff surgical wire material and the resulting pieces of the lens nucleus are aspirated. Typically the lens is stabilized by a phacoemulsifier while the hook is drawn across the nucleus. The hook has typically been of approximate "L" shape, with a portion extending at substantially a right angle to the shaft of the instrument.
In order to disassemble the appropriate size nuclear fragments without encountering difficulties in containing the nuclear fragments within the posterior capsular sac away from the corneal endothelium, it has been known to create a central trough or crater in the nucleus using the phacoemulsifier alone or in combination with the hook, followed by splitting the nucleus into two halves with the hook. These two large nuclear pieces, due to their bulk, remain stable within the posterior capsular sac. The hook is drawn across the nuclear pieces following the natural cleavage planes progressively splitting off only small wedges in a circumferential direction. Although the technique as described has had a modicum of success, difficulties have been encountered in that the hook has tended to slip and lose contact with the nucleus during the drawing motion.